<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>Three.js - Shadertoy - Procedural Texture</title>
    <style>
    html, body {
        height: 100%;
        margin: 0;
    }
    #c {
        width: 100%;
        height: 100%;
        display: block;
    }
    </style>
  </head>
  <body>
    <canvas id="c"></canvas>
  </body>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>

<script type="importmap">
{
  "imports": {
    "three": "../../build/three.module.js"
  }
}
</script>

<script type="module">
import * as THREE from 'three';

function main() {
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});

  const fov = 75;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 5;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.z = 2;

  const scene = new THREE.Scene();
  const boxWidth = 1;
  const boxHeight = 1;
  const boxDepth = 1;
  const geometry = new THREE.BoxGeometry(boxWidth, boxHeight, boxDepth);
  const fragmentShader = `
  #include <common>

  uniform vec3 iResolution;
  uniform float iTime;
  uniform sampler2D iChannel0;

  // By Daedelus: https://www.shadertoy.com/user/Daedelus
  // license: Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
  #define TIMESCALE 0.25 
  #define TILES 8
  #define COLOR 0.7, 1.6, 2.8

  void mainImage( out vec4 fragColor, in vec2 fragCoord )
  {
    vec2 uv = fragCoord.xy / iResolution.xy;
    uv.x *= iResolution.x / iResolution.y;
    
    vec4 noise = texture2D(iChannel0, floor(uv * float(TILES)) / float(TILES));
    float p = 1.0 - mod(noise.r + noise.g + noise.b + iTime * float(TIMESCALE), 1.0);
    p = min(max(p * 3.0 - 1.8, 0.1), 2.0);
    
    vec2 r = mod(uv * float(TILES), 1.0);
    r = vec2(pow(r.x - 0.5, 2.0), pow(r.y - 0.5, 2.0));
    p *= 1.0 - pow(min(1.0, 12.0 * dot(r, r)), 2.0);
    
    fragColor = vec4(COLOR, 1.0) * p;
  }

  varying vec2 vUv;

  void main() {
    mainImage(gl_FragColor, vUv * iResolution.xy);
  }
  `;
  const vertexShader = `
    varying vec2 vUv;
    void main() {
      vUv = uv;
      gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );
    }
  `;

  const loader = new THREE.TextureLoader();
  const texture = loader.load('resources/images/bayer.png');
  texture.minFilter = THREE.NearestFilter;
  texture.magFilter = THREE.NearestFilter;
  texture.wrapS = THREE.RepeatWrapping;
  texture.wrapT = THREE.RepeatWrapping;
  const uniforms = {
    iTime: { value: 0 },
    iResolution:  { value: new THREE.Vector3(1, 1, 1) },
    iChannel0: { value: texture },
  };
  const material = new THREE.ShaderMaterial({
    vertexShader,
    fragmentShader,
    uniforms,
  });
  function makeInstance(geometry, x) {
    const cube = new THREE.Mesh(geometry, material);
    scene.add(cube);

    cube.position.x = x;

    return cube;
  }

  const cubes = [
    makeInstance(geometry,  0),
    makeInstance(geometry, -2),
    makeInstance(geometry,  2),
  ];

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  function render(time) {
    time *= 0.001;  // convert to seconds

    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }

    cubes.forEach((cube, ndx) => {
      const speed = 1 + ndx * .1;
      const rot = time * speed;
      cube.rotation.x = rot;
      cube.rotation.y = rot;
    });

    uniforms.iTime.value = time;

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);
}

main();
</script>
</html>

